This invention concerns removal of a film or sheen of liquid which floats atop another liquid. In one specific embodiment the invention is concerned with skimming to remove a thin layer of a petroleum derivative from the surface of a body of water, particularly gasoline or oil sheen in a boating marina; the efficient removal of heavier layers of oil from bodies of water is also an objective of the invention.
Skimmers have been known in several forms. Floating skimmers may have fixed weirs or floating weirs, and as is well known, a relationship must be established between the surrounding body of liquid, the weir height and a sump behind the weir, in order to achieve a skim. Attention is directed to U.S. Pat. Nos. 3,970,556, 5,308,510 and 5,478,483.
In boating marinas and similar situations involving the dispensing or handling of oil, gasoline, diesel fuel or other lighter than water pollutants over or near a body of water, there has been a need for an efficient mechanism or procedure to remove the thin film or sheen of petroleum product which will float and quickly spread on the water when spilled. Over-filling of fuel tanks very often causes a pint or a quart of fuel to spill into the water, and this is objectionable in pristine lakes, rivers, bays and other bodies of water. In addition to the situation at marinas, many small spills occur into our environment because of vehicles which have hydrocarbon powered engines, and thus have fuel tanks which may rupture in the case of accidents. Often the spilled fuel runs to waterways and is difficult to clean up. This also occurs when hydrocarbons are carried around in barrels (drums) which are prone to damage in the case of accidents.
In such circumstances as well as other situations in which petroleum products are spilled in bodies of water, including in vessel bilges, there is a need for an efficient and cost-effective way to remove the petroleum products and separate them from water such that the water can be returned to its source or otherwise harmlessly to the environment without expensive transportation and further handling. Previous to this invention such spills of oil and other petroleum products have required large equipment and the accumulation and handling of a large and inefficient volume of liquid. Currently there has been no practical, economically feasible method of cleaning up these types of spill, because the concentrations of hydrocarbons on water are so slight that cleanup requires trucking away tons of water, and paying to have the water accepted as hazardous waste at an appropriate facility. Currently there has been no way of cleaning the water resulting from the skimming operation to allow the discharge of the water back into the environment.
There is also a need for an efficient skimmer apparatus and method for removing a floating layer of liquid from a body of another liquid, other than water, in certain industrial situations and liquid purification operations.
The present invention is directed toward providing a small, easily-used portable skimmer for removing a surface sheen or layer of liquid floating on water or on other heavier liquid, which skimmer may be used with a filter medium to thoroughly remove hydrocarbons from water, to the extent that the water may be returned to its source. The invention provides an easy to deploy method of removing the hydrocarbons from a relatively small spill, without the necessity of trucking away the water drawn in during skimming operations.